The Association of the German Automotive Industry (VDA) has proposed a standardized e-gas monitoring concept for the engine control of gasoline and diesel engines. The e-gas monitoring concept makes provision for the fact that in lean operation of an internal combustion engine, it is necessary to change over irreversibly to quasi-stoichiometric operation of the internal combustion engine when an implausible operating variable of the internal combustion engine occurs.
The effects of the implausible operating variable during the quasi-stoichiometric operation of the internal combustion engine are normally less critical than possible effects of the implausible operating variables in lean operation of the internal combustion engine. However, the efficiency of the internal combustion engine is higher in lean operation than that of the quasi-stoichiometric operation.